Interesting. While far southern NH is part of the NE megaregion, most of NH, all of Vermont, and nearly all of Maine are outside any of these megaregions.
Looking at the map, it’s easy to see that the mountains in the north of these states, and south through the Appalachian Mts prevent the megaregions from joining, except digitally.
Rise of America’s megaregions | Watch
https://www.msn.com/en-us/society-culture-and-history/history/the-hidden-truth-the-us-is-actually-12-nations-disguised-as-50-states/vi-AA1E9P1c